document.write( "Question 115561This question is from textbook
\n" ); document.write( ": Automotive trades:
\n" ); document.write( "Total piston displacement is given by the following formula:\r
\n" ); document.write( "\n" ); document.write( "P.D. = piD^2LN (pi is over 4)\r
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\n" ); document.write( "\n" ); document.write( "where:\r
\n" ); document.write( "\n" ); document.write( "P.D. = piston displacement in cubic in.
\n" ); document.write( "D = diameter of bore of cylinder
\n" ); document.write( "L= length of stroke, in inches
\n" ); document.write( "N = Number of cylinders\r
\n" ); document.write( "\n" ); document.write( "A. P.D. = 400 cu in. L = 4.5 in. N = 8\r
\n" ); document.write( "\n" ); document.write( "B. P.D. = 392.7 cu. in. L = 4 in. N = 6
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Algebra.Com's Answer #84116 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given the formula for total piston displacement as:
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\n" ); document.write( "\"PD+=+%28%28pi%2AD%5E2%29%2F4%29%2AL%2AN\"
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\n" ); document.write( "Let's analyze this formula just a little to see what it is telling us.
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\n" ); document.write( "The part of the formula that is \"pi%2AD%5E2%2F4\" is just the old geometry formula for finding
\n" ); document.write( "the area of a circle when you are given the diameter of the circle. In this case you are given
\n" ); document.write( "the diameter of the bore, and you are calculating the cross-sectional area of the cylinder.
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\n" ); document.write( "Next you multiply that area by the length of the stroke. What you are finding by doing this
\n" ); document.write( "is the volume displacement for a single cylinder. What you have done this far is just the
\n" ); document.write( "same as the old geometry problem of finding the volume of right cylinder by multiplying
\n" ); document.write( "the area of its circular base times the height of the cylinder.
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\n" ); document.write( "Finally you multiply this by volume for a single cylinder in the car by the number of cylinders
\n" ); document.write( "in the engine to find the total volume displacement or Piston Displacement.
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\n" ); document.write( "You give two problems in which you specify the total Piston Displacement, the length of the stroke,
\n" ); document.write( "and the number of cylinders. I guess that you want to find the diameter of the cylinder bore.
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\n" ); document.write( "For the first problem the total PD is 400 cubic inches ...(about 6.6 liter - a gas guzzler).
\n" ); document.write( "The length of the stroke is 4.5 inches, and there are 8 cylinders. Substituting all these
\n" ); document.write( "values into the equation you get:
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\n" ); document.write( "\"400+=+%28%28pi%2AD%5E2%29%2F4%29%2A4.5%2A8\"
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\n" ); document.write( "The L and the N multiply out to give 4.5 * 8 = 36. Substitute this into the equation:
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\n" ); document.write( "\"400+=+%28%28pi%2AD%5E2%29%2F4%29%2A36\"
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\n" ); document.write( "Divide both sides of this equation by 36 to get rid of the factor 36 on the right side.
\n" ); document.write( "On the left side 400 divided by 36 becomes 11.11111111. And on the right side the 36 is
\n" ); document.write( "divided by 36 which equals 1. So the reduced equation is:
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\n" ); document.write( "\"11.11111111+=+%28pi%2AD%5E2%29%2F4\"
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\n" ); document.write( "Get rid of the denominator of 4 on the right side by multiplying both sides of the equation
\n" ); document.write( "by 4 to get:
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\n" ); document.write( "\"44.44444444+=+pi%2AD%5E2\"
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\n" ); document.write( "Divide both sides of the equation by \"pi\" which approximately equals 3.141592654.
\n" ); document.write( "The left side of the equation becomes:
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\n" ); document.write( "\"44.44444444%2F3.141592654\" and this divides out to give \"14.14710605\"
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\n" ); document.write( "On the right side the \"pi%2Fpi\" becomes just a factor of 1. So the equation you are left
\n" ); document.write( "with is:
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\n" ); document.write( "\"14.14710605+=+D%5E2\"
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\n" ); document.write( "Solve for D by taking the square root of both sides to get:
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\n" ); document.write( "\"D+=+sqrt%2814.14710605%29+=+3.76126389\"
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\n" ); document.write( "So the answer to this problem is that the bore has a diameter of 3.76126389 inches. You
\n" ); document.write( "can round off this answer to the accuracy you need.
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\n" ); document.write( "The second problem is the same ... only the numbers have changed ... This time the equation with
\n" ); document.write( "the appropriate numbers inserted is:
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\n" ); document.write( "\"392.7+=+%28%28pi%2AD%5E2%29%2F4%29%2A4%2A6\"
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\n" ); document.write( "And the stroke times the number of cylinders is 24 ... making the equation:
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\n" ); document.write( "\"392.7+=+%28%28pi%2AD%5E2%29%2F4%29%2A24\"
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\n" ); document.write( "Divide both sides by 24:
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\n" ); document.write( "\"16.3265+=+%28pi%2AD%5E2%29%2F4\"
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\n" ); document.write( "Multiply both sides by 4:
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\n" ); document.write( "\"65.45+=+%28pi%2AD%5E2%29\"
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\n" ); document.write( "Divide by \"pi\"
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\n" ); document.write( "\"20.83338205+=+D%5E2\"
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\n" ); document.write( "Solve for D by taking the square root of both sides:
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\n" ); document.write( "\"D+=+sqrt%2820.83338205%29+=+4.564359983\"
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\n" ); document.write( "So this time the diameter of the cylinder bore is 4.564359983 inches ... (probably not
\n" ); document.write( "a very economical 6 cylinder engine).
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\n" ); document.write( "Hope this is what you were looking for and it helps you to understand the problem. \r
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